1. Field of the Invention
The present invention relates to a method for cultivation of microorganisms or animal cells or plant cells, in particular, recombinant microorganisms with acetate concentration monitoring to efficiently produce desired useful substances such as enzymes or biologically active substances. The present invention also relates to an apparatus for the method.
2. Prior Art Statement
By cultivation of microorganisms or animal cells or plant cells, especially recombinant microorganisms, there has been hitherto produced enzymes, antibiotics, amino acids, or biologically active substances such as hormones or the like which are metabolites. This method for cultivation is mostly batch culture which comprises simply charging medium and seed cells in a culture tank. As a matter of course, the productivity is low.
In order to enhance the productivity, there is performed a culture method in which a substrate or inducer is added during the course of cultivation. However, it is a problem that at which point of the cultivation the substrate or inducer should be added and its clear indicator is unknown. On the other hand, in cultivation using baker's yeast, there is known a method which comprises detecting the production of ethanol with respiratory quatient and feeding substrate [Japanese Patent KOKAI (Laid-Open) Nos. 36983/1982 and 78584/1983]. However, this is cultivation for producing cell mass per se which are quite dissimilar to producing the metabolites.
Further in spite of adding substrate, there is a phenomenon that the growth rate of cells decreases during cultivation. This is said to be due to proliferation-inhibitory substances accumulated in culture broth. However, there is little finding on the proliferation-inhibitory substances. Also from this aspect, efficient cultivation can be achieved only with difficulty. In order to remove the proliferation-inhibitory substances without specifying them, there is known a method which comprises withdrawing culture broth intermittently or continuously, recovering the cells by centrifugation and charging the cells again in a culture tank [Japanese Patent KOKAI (Laid-Open) No. 29985/1978]. However, this method is directed to baker's yeast and mass production of cells per se, not a process for allowing the cells to produce the desired substances.
The prior art described above was developed without consideration of adding substrate or the like or monitoring proliferation-inhibitory substances and involved problems of difficulty in cell growth and production of metabolites.